Drive for valve cutoff indicators



Nov. 28, 1944. F. D. wr-:LDEN

DRIVE FOR VALVE CUT-OFF INDICATORS Filed July 29, 1941 ATTORNEYS Patented Nov. 28s, 1944 Fay D. Welden, Tuckahoe, N. Y., assignor to Valve Pilot Corporation, New York, N. Y., a corporation of New York Application July 29,1941, Serial No. 404,497

2 Claims. (Cl. 116-114) This invention relates to means for operating a valve cut-off indicator on a poppet valve steam engine. In Caracristi Patents Nos. 1,627,076 and 1,704,3{51instruments are described by whichall of the factors governing cut-off which produce the maximum result at different speeds are converted into a single expression and combined with speed indicating mechanism. A pair of needles move over a common scale, one of these needles giving the converted reading based on the variousV factors governing cut-olf, the other needle indicating speed. `The cut-off needle is actuated through a cam-,box which in turn is actuated by a connection through the tumbling shaft, the angular position of which is controlled by the reverse lever. By keeping the two needles in registry the engineer is assured that he is using the proper cut-olf for maximum output for each speed. The engines for which the cut-off indieating instruments of these two patents are designed are engines of the slide valve type in which the engine is reversed and the cut-off varied by means of arms swung about the tumbling shaft.`

In engines of the poppet valve type, however, there is no tumbling shaft and these operations are performed through a rotary shaft which, in modern locomotives, connects the power reverse gear in the cab with` the gear box operating the poppet valves. It is the object of this invention to provide means for operating a cut-off indicator `of the kind described from the connecting shaft of a poppet valve steam engine.

In the drawing I have illustrated means by which I operate the cut-off indicator from the connecting shaft of a poppet valve engine, the drawing illustrating in side elevation, the cam box of the cut-off indicator with its operating connections, and a section `of the connecting shaft. l

In this drawing I indicates the connecting shaft extending between the power reverse gear `in the cab and the gear box operating the valves, and 2 the cam box which houses the mechanism which converts into a single expression all of the fac-` f tors governing cut-off which produce maximum results at different speeds. The mechanism within the cam box is actuated by means of a rod 3 longitudinally movable in direct response to changes in cut-off, as will be explained presently. Leadingffrom the cam box to an indicating and recording instrument in the cab is a cable 4, movable Within a conduit 5, which actuates the indicating and recording instrument in accordance with the law of the cam box mechanism indicating and recording mechanism itself forms `no part of the present invention and for a detailed description of it the reader is referred to the two Caracristi patents mentioned above.

An intermediate section of the connecting shaft I is provided with a worm 6 mounted between universal joints l to compensate for yany misalignments of the driving and driven ends of the shaft. This worm (i` meshes with and drives a worm gear 8 fixed upon a transverse shaft'9 journaled on the engine frame. Fixed to the shaft 9 by means of a pair of arms I0 is a block II on which is mounted a second block I2 through threaded posts I3 and nuts I4. The position of the block I2 with reference to the block I I is initially determined by the position of the nuts I4, and when thatposition has once beencorrectly set, the nuts can be welded in position. A yoke I5 stradles the block.r I2 and is pivotally connected to it by means of studs I6. This yoke is, in turn, connected to the rod 3 leading to the cam box. The rod is provided with a turnbuckle I'I by means of which its length may be adjusted. t

t The throw of the rod 3 is such that the shaft 9 oscillates from mid gear forward position to forward corner position through 20, and from mid gear forward position to reverse corne-r position also through 20. Within this 40 arc all variations of cut-01T are taken care of. `The connecting shaft makes six full revolutions in one direc-` tion from mid gear forward position to forward corner position, and the same number in the other direction to reverse corner position. Th'e worm 6 and worm gear 8 are, therefore, designed so` that six revolutions of the former turns the latter s through 20. I

The engineer operates his power reverse gear in the usual manner to vary the cut-off. The resultant rotation of the connecting shaft I acts through the worm gearing to swing the block I2, either forward or backward, through a corresponding arc, and this, through the pivoted yoke I5, moves the rod 3, which, through the cam box mechanism and the cable 4, moves the cut-olf verse to the rotary shaft, a block carried by the as the cut-01T is varied. The cut-off converting, 55 oscillatoryshaft and pivotally connected to the rod, a worm on the rotary shaft and a worm wheel on the oscillatory shaft meshing with and driven by the worm.

2.- In a poppet valve steam engine, a rotary yshaft forvarying the cut-01T, a cam box for coni`verting into a single expression factors governing cut-01T which produce the maximum result at differentl speeds, a longitudinally movable rod for actuating the cam box, an oscillatory shaft transverse to the rotary shaft, a, block carried by the 10 oscillatory shaft and pivotally connected to the shaft through arcs determined by the throw ofv the rod. s s

` FAY D. WEIDEN. 

